var list = objTable.AsEnumerable();

        var query = from l in list
            where l.Field<string>("root") == "1"
            select l;

        var result = query.Concat(from q in query
            from l in list
            where l.Field<string>("root") == q.Field<string>("id")
            select l);

        foreach (var r in result)
        {
            Console.WriteLine("value has id:{0}, root:{1}", r.Field<string>("id"), r.Field<string>("root"));
        }